Apparatuses with adjustable compliance have recently become more prevalent. Such apparatuses can minimize large forces due to shocks, enable safe interactions with a user, and store and release energy in passive elastic elements, while having variable stiffness. These apparatuses can be employed in various applications where an elastic attribute is desirably variable.
An example of an application in which an apparatus with adjustable compliance can be employed is a robotic application, where such apparatus can enhance safe human-robot interaction. Another example application that can use an apparatus with adjustable compliance is a robot hand. Following this example, it can be desirable to have the robot hand be more compliant (e.g., more give, softer, less stiff, etc.) when initially grabbing an object, and then transition to becoming less compliant (e.g., less give, firmer, more stiff, etc.) to provide a firm grasp of the object. Yet, it is also to be appreciated that apparatuses with adjustable compliance are being utilized in various other types of applications.
Conventional apparatuses with adjustable compliance are oftentimes complex and costly. Other common apparatuses with adjustable compliance such as, for instance, conventional apparatuses that have a tension or compression spring with an adjustable number of active coils, are too large and oftentimes have improper geometry for various applications (e.g., due to being loaded axially in tension or compression).